Synchronous selector apparatus



Nov. 19, 1940. c. F. WALLACE S YNCHRONOUS SELECTOR APPARATUS Filed Dec.18, 1936 3 Shets-Sheet 1 s Pia'o/vin/ce Ma'roe BY K INVENTQR F. waif!ATTORNEYS Nov. 19, 1940. c. F. WALLACE 2,222,218

SYNQHRQNOUS SELECTOR APPARATUS Filed Dec. 18, 1936 v 3 Sheets-Sheet 2 67RADIO Pwamfi/vce RECEIVER Norm? EHVENTOR M F. wmwu can-min, KIA-A.LSMA/Wi 5 ATTORNEY-S Nov. 19, 1940. c. F. WALLACE 2,222,213

' SYNCHRONOUS SELECTOR APPARATUS Filed Dec. 18, 1956 3 Shets-Sheet 3MFTUJQUML BY wru, KM-AMLM ATTORNEYS Patented Nov. 19, 1940 UNITED STATESPATENT OFFICE SYNCHRONOUS SELECTOR APPARATUS Application December 18,1936, Serial No. 116,511

11 Claims.

This invention relates to synchronous selector apparatus, and moreparticularly to apparatus whereby operation of circuit-controlling orlike elements at one station may be selectively effected in accordancewith the operation of a controlled device at a remote station.

One object of the invention is to providea synchronous selector system,and indicator and selector mechanisms therein at the controlling andcontrolled stations, respectively, which are of superior efliciency,simple and fool-proof in operation, economical in construction,non-huntingand positive in synchronization, and adapted for a wide rangeof uses, particularly in the re mote control of electrically actuated orcontrolled apparatus. A further object is to provide synchronousselector apparatus whereby remote control by radio or the like may bereadily eifected for stations such as marine light and fog signal sstations, so that the desired lights and signals at the remote stationmay be operated, and telemetering apparatus selected at the remotestation for transmitting back by radio to the controlling or masterstation, any of a plurality of meter readings or like indications of thecondition of the apparatus at the controlled station.

Another and important object of the invention is to provide anarrangement of the character described, wherein the'operator at themaster or controlling station merely depresses a key or the like,whereupon an indicator is automatically set in operation and caused tostop at a desired dial position under the control of the operator, andwherein at the same time and in synchronization with the mechanism atthe master station, a selector device is automatically operated at theremote station to select a control position at the remote stationcorresponding to the selected indicator position at the master station,and to 40 effect, when in the selected control position, a predeterminedcontrolling operation, as by the closure of a set of electricalcontacts.

A further object of the invention is to provide a selector arrangement,particularly having the operating characteristics Just described,wherein synchronization and re-setting of the apparatus may be effectedautomatically, and, so to speak,

simultaneously, upon the operation of a simple control at the masterstation, and wherein such synchronization of the selecting device at theremote station with the indicator device at the controlling station maybe brought about or maintained simply by depressing the selector controlkey at the master station for a brief period of time; and a furtherobject of the invention is to provide selector apparatus whe ein thefunctioning of the circuit controlling device at the remote station ispositively controlled by electro-mechanical means, so as to insureagainst false or inadvertent operation and to provide a positiveresponse to the selection efiected, for example, by the operator at themaster station.

Further objects and advantages are such as will be apparent from thefollowing description 01' what is now considered to be a preferredembodiment of'the invention, including such objects and advantages asmay be inherent in such apparatus and mechanism, although notspecifically adverted to herein.

Referring to the drawings, which illustrate the presently preferredembodiment:

Fig. 1 is a front elevation of the selector indicator at the master orcontrolling station;

Fig. 2 is a rear elevation of said mechanism;

Fig. 3 is a side elevation thereof Fig. 4 is a wiring diagram of thecontrolling and indicating apparatus at the master station;

Fig. 5 is a front elevation of the selector unit or switching device atthe remote or controlled station;

Fig. 6 is a rear elevation of said mechanism;

Fig. 7 is a side elevation thereof;

Fig. 8 is a wiring diagram of the selector and switching apparatus atthe controlled station;

Figs. 9 and 10 are side elevations, partly in section, of one set of theselector-controlled contacts of the mechanism shown in Figs. 5 to '7,inclusive, Fig. 9 showing the contacts in closed position, and Fig. 10showing them in open position; and

Fig. 11 represents a modified contact arrangement similar to Fig. 10.

Referring first to Figs. 4 and 8, it may be explained that the systemhere shown is particularly adapted for the remote control or a pluralityof switching stations by radio, Fig. 4 representing the wiring diagramat the master station, and Fig. 8 the wiring diagram at the remote orcontrolled station, the arrangement being such that when the operator atthe master station depresses a key 20, an indicator arm 2| is set intoclockwise rotation, and is stopped at the will of the operator upon hisreleasing the key 2|], presumably when the arm 2| has arrived at thedesired position on the diali. e., the position which, identified (asare the other selectable positions) by an appropriate number, is knownto correspond to the contacts or circuitcontrolling device that it isdesired to operate at the remote station. At the same time, a selectormember 22 (see Fig. 8) is automatically set into clockwise rotation atthe controlled or remote station, and moving synchronously with the arm2! at the master station, stops at the time that the arm 2| does, and ata position corresponding 5 to the selected control position in which thearm 2| (of the indicator) hasstopped. That is, the selector member 22thus stops at the desired one of the several selectable switches or setsof contacts 23, and automatically brings about and maintains the desiredcircuit controlling operation of that particular switch or set ofcontacts.

Turning now to Figs..1 and 3, the indicator mechanism for the masterstation may be mounted upon a panel 24 of insulating material, such asBakelite, having a series of numbers or other indicia on one face, toprovide a dial for the indicator, (as shown in Fig. l). The indicatingarm 2| is mounted on a shaft 28 passing through the plate 24 so that thearm 2| may be rotated by the shaft, and thus point to the successivenumbers on the dial. The shaft 26 is connected, throughv a train ofgears 21, 28, 23, 30, for drive from the shaft 3| of'a motor generallydesignated 32, the gearing being conveniently such as to reduce thedriving speed, whereby the indicator arm 2| will be rotated slowly inrelation to the speed of rotation of the motor shaft 3|. The motor 32 ispreferably an alternating current motor of the I type described andclaimed in United States Letters Patent No. 1,995,270, granted March 19,1935, upon application filed by me, Charles F. Wallace, for Electricmotor. This motor is a so-called resonance motor, has practically noinertia, and, therefore, can start and 35 stop almost instantly. Thatis, it is not only a motor which may require very little power for itsoperation, but is one which has practically no starting lag and does notcoast" appreciably when the power is turned oil. It will be understoodthat although I prefer to employ the motor. of my patent just mentioned,other driving means may be used, such as other motors which have thecharacteristics Just stated or have starting and arresting attachmentsadapted to provide those characteristics.

An electro-magnet 35 is also conveniently mounted on the rear of thepanel 24, and has an armature 36 at one end of which is pivoted a rod31, siidably projecting through the face of the panel 24. Thearrangement of the electro-magnet or solenoid 35 is such that when themagnet is energized and its armature 38 drawn down against its polepiece 38, the rod 31 is pushed through the panel a short distance intothe path of a pin 39 on the under face of the indicator arm 2|. The rod31 thus acts as a detent for the member 2|, the magnet and rod beingconveniently so positioned, as shown in Figs. 1 to :3, that the arm ormember 2| will be thereby arrested in its lowermost or "zero position.

Likewise conveniently mounted on the rear of the panel 24 are atransformer 40 which may be of the step-down type to provide, from anordinary commercial alternating current line,

5 low-voltage alternating current for the operation of the motor 32; anda rectifier device 4|, comprising, for example, four units of thecopper-oxide type connected in the usual bridge arrangement. A pushbutton or key, 20, having normally open contacts 42, adapted to beoperated by a manually depressible button 43 on the face of panel 24, isalso provided, this push button or key being normally maintained inopencircuit position by the inherent resilience of the contact strips,or by other suitable means.

The manner in which the foregoing parts are electrically connected willbe apparent from the wiring diagram (Fig. 4) and the following operativedescription of that diagram Upon depressing the key or push button 20,and main- 5 taining the same in depressed position, alternating currentis supplied from a suitable source such as the ordinary -volt, (SO-cycleline, to the primary of transformer 40. The .motor 32, connected acrossthe secondary of transformer 10 40 by means of conductors 45, 46, isthus set in operation and immediately commences to drive the indicatorarm 2| in a clockwise direction as viewed in Figs. 1 and 4--it beingassumed, for reasons hereinafter apparent, that the arm 2| has 15 beenoriginally set at itslowermost or zero position. At the same timealternating current is also supplied from the secondary of transformer40, to input terminals 41, 48, on the rectifier bridge 4|, wherebyuni-directional E. M. F. is 20 set up at the output terminals 49, 60, ofthe bridge. The electro-magnet 35, being connected across the rectifieroutput 49, 50, is thus energized by the uni-directional current suppliedtherefrom, and attracts its armature 36, so as 2a to bring the detent 31into position for arresting the arm 2| when and if it again arrives atthe zero position.

There is also provided radio wave transmitting apparatus 5|, which maybe of any type 30 adapted to transmit a carrier by reason of antenna 52and ground 53, and which is adapted to impress modulation upon saidcarrier in accordance with, and at the frequency of, alternating currentsupplied as a modulating current 35 to the terminals 54 of thetransmitting apparatus. A suitable transformer 55 is connected acrossthe secondary of transformer 45, as by the conductors 45, 46 leading tothe motor 32, and has its secondary connected to the terminals 40 54 ofthe transmitter. It will be understood that this transformer 55 is suchas to provide, from the low voltage A. C. supplied by transformer 40,modulating alternating current at the appropriate voltage for modulationof the trans- 45 mitted carrier. Thus, so long as key 23 is depressed,not only is the motor 32 set in operation, and energizinguni-directional or direct current delivered to magnet 35, but thecarrier transmitted by transmitter 5| is modulated at the 0 frequency ofthe alternating current delivered by the input line and transformer 4|].I

Referring now to Figs. 5 to 10, inclusive, it will be seen that theselector apparatus at the remote station may comprise a'similar panel64, 55 upon the face of which are mounted a plurality of contacts orswitching devices generally desig nated 23, and arranged in circularformation, so as to be engaged, when and if desired, by rotatable member22. As shown in Figs. 9 and 10, 60 each of the switches 23 may comprisea pair of normally open contacts 65, 66 mounted upon a suitableinsulating support and normally open by virtue of their inherentresilience.

Mounted. on the rear of the panel is a motor 61, preferably andconveniently identical with, or of the same type as, the motor 32employed in the indicator mechanism, as described hereinabove. 70

The shaft 68 of the motor 61 is connected by reducing gearing 69, 10, IIand I2, conveniently providing a reduction in speed identical to thatprovided by the gearing in the indicator mechanism, to drive a hollowshaft 73, which 75 projects through the panel 64 and has mountedthereon, for rotation therewith, a member ll.

Member 22 is pivotally supported by a pair of upstanding arms l5, 15, onthe member H, so that member 22 may be rocked about an axis which is ina plane perpendicular to, and is disposed laterally of, the axis ofshaft 18, as shown in Fig. 5. Springs 18 are provided intermediate themember 22 and member 14 so as to bias member 22 in a counter-clock-wisedirection, as seen in Figs. 9 and 10-1. e., so that the end of member 22which is nearest shaft 18 is biased toward the panel 84. The outer endof member 22 is provided with a camming pf-ojection 18, conveniently ofinsulating material, which is adapted to pass below the contact strips88 of the successive switching devices 22, and to engage the latter andclose their contacts whenever memiber 22 is in the position to which itis biased by the springs 18, as shown in Fig. 9.

There is also provided an electro-magnet or solenoid 80, having anarmature 8| and a. member 82 mounted on the armature and adapted. topush against a rod 83 which passes through the hollow interior oftubular shaft 18. The rod 88. longitudinally slidable within the shaft18, thus abuts at one end the operating arm 82 of the armature 8|, andat the other end, where it has passed through the panel, the under sideof the inner end of member 22. It will now be seen that by virtue of themanner in which member 22 is biased by its springs 18, and the manner inwhich the armature 8| is biased in retracted position, as by its spring84, the member 22 normally occupies the position shown in Fig. 9; butthat upon energization of the magnet 80, rod 83 is pushed to the right,as seen in Fig. 7, or upwardly as seen in Figs. 9 and 10, so as to rockthe member 22 into the position shown in Fig. 10, in which position themember 22 does not operate, i. e. close, the contacts 23 by'urgingtogether their arms 65, 66.

Likewise conveniently mounted on the rear of panel 64 are a rectifier85, which may be of the same type as rectifier 4|, and a transformer 85conveniently of the step-down type to be supplied with alternating orpulsating current from the output of a radio receiving apparatus, andadapted to provide a low voltage alternating current to operate themotor 61.

Referring now to the wiring diagram of Fig. 8, it will be seen that whenthe radio receiving apparatus 81, which is tuned to the carrier emittedby the transmitting apparatus picks up the modulated carrier from thatapparatus, a pulsating or alternating current of frequency correspondingto that of the modulation, is delivered to the primary of transformer86. It will be understood that the radio receiving apparatus may beofany suitable type, of which many types are known, including appropriateapparatus for amplifying at radio frequency, detecting, and amplifyingat audio frequency, a modulated carrier. Thus assuming that themodulated carrier transmitted from the apparatus of Fig. 4 is picked upat the station of Fig. 8, the motor 61 connected across the secondary oftransformer 88 by conductors 88, 89 is supplied with alternating currentof the same frequency as that delivered to motor 82 at the master orcontrolling station. The motor 81 is thus immediately set intooperation, and drives the member 22 in a clockwise direction as seen inFigs. 5 and 8-it being understood for reasons hereinafter apparent, thatmember 22 has been set to the starting or zero position indicated by thehereinafter-described pin 88 on the face of panel 84. At the same time,alternating current is delivered from the secondary of transformer 88 tothe input of rectifier 88, having the same type of bridge arrangementpreviously described, and uni-directional current is thereby derivedfrom the rectifier, for energizing the electro-magnet or solenoid 88.The armature of magnet 80 is attracted, shifting the rod 88 and rockingthe member 22 out of switchoperating-i. e. contact closing-position.Thus as long as the motor 51 and consequently member 22 are driven bycurrent supplied from transformer 86, the energization of magnet 88keeps the member 22 from operating or closing any of the switchingdevices 28.

It will thus be seen that assuming the indicator member 2| of theindicator apparatus, and the switch-operating member 22 of the selectorapparatus, have both started out in their zero positions, they will movesimultaneously and in synchronism so long as key 20 is depressed. Theoperator at the master or controlling station (Fig. 4) watches the dial24 while he depresses the key, and when the rotating arm 2| comes to thenumbered position corresponding to the switch which he wishes to operateat the remote station, he releases the key. The member 2| stops at thisposition,.and at the same time, so does the member 22 stop at thecorresponding position, and with its member 18 under the arm 65 of thecorresponding switch, in the selector apparatus at the remote station.At the same time, since alternating current for modulation is then nolonger delivered to the transmitter at the master station, a modulatedcarrier is no longer received at the remote station (Fig. 8) and nopulsating or alternating current is delivered to the primary oftransformer 86. Thus no current is delivered by the secondary of thetransformer and not only does the motor 6'! stop, but the magnet 88 isdeeenergized, releasing its armature and the rod 83, and permitting themember 22 to rock (counter-clockwise as seen in Fig. 9) into switchoperating (contact-closing) position. Thereafter, the switch thusselected will be maintained in the position into which it has beenshifted by member 22, so that, for example, its contacts will be closedthereafter and as long as key 20 is not again depressed.

As previously stated, there is provided a pin 90, projecting from theface of the panel 64 (Fig. 5) of the selector apparatus and disposed atthe "zero" position of the switch-operating member 22. A correspondingpin or abutment 9| (see Figs. 9 and projects from the lower surface ofmember 22 at the outer end of., .the latter, and the arrangement of pins80 and 9| is such that when member 22 is kept in the position of Fig. 10(for non-operation of the switching devices) by energization of magnet88 and the associated instrumentalities, pin 9| will strike against pin90 upon rotation of the member 22 to the "zero poistion-pin 80 thusoperating as a detent for the member 22.

It will now be seen that by virtue of the arrangement just described,and by virtue of the arrangement of members 31 and 89 in the indicatormechanism, members 2| and 22 of the indicator and selector mechanisms,respectively, will be stopped at their respective "zero positions whenthey are being rotated by their respective motors under control of thekey 28 at the master station. It will be understood that theconstruction of the motors 32 and G1 (motors, for example, of the typeof the above-mentioned Wallace patent) is such that when members 2| and22 are arrested and further rotation of the motor drive shafts thusprevented, no injury will be done to the corresponding motor. That is,although the energizing circuit for the motor may not have beeninterrupted, the shaft of the motor may be held against rotation,without harm to the motor itself.

It will now be seen that resetting and synchronization of both theindicator and selector mechanisms may be simultaneously and very easilyaccomplished. In order to do that-for instance, after the apparatus hasbeen used for effecting control of one of the switching devices 23 atthe remote stationthe operator at the master station need only depresshis key 20 for the period of time, or preferably for slightly longerthan the period of time, during which the respective members 2| and 22would make a complete revolution under drive of their motors. In theapparatus here shown, the motors 32 and 61, with their associatedgearing, may conveniently be adapted to effect a complete rotation oftheir corresponding members 2| and 22 in the predetermined period, forexample, of 30 seconds (or in a shorter or longer period, as desired),and consequently if the operator wishes to set or reset the indicatorand selector devices, so as to be ready for a controlling operation, heneed merely depress the key 20 for a period slightly in excess of 30seconds (or other predetermined time of rotation) A To explain thatoperation more fully: Suppose that the member 2| has previously beenstopped opposite the number 5, on the dial of the indicator mechanism(Fig. 1). Presumably, the member 22 of the selector is stationed at thecorresponding switching device 23 (particularly 40f identified ascontacts 235 in Fig. 5), or it may be 45 either case.

that the members 2| and 22, as by an inadvertent manual displacement,are not stopped at corresponding positions in their respective paths ofrotation; the resetting operation is the same in When the key 20 is nowdepressed, member 2| will be setin rotation by the motor 32, and magnet35 will be energized so as to op erate member 31 and bring the latterinto the path oi pin -39 on member 2| (see Figs. 1 and 3) As theoperator continues to hold down the key 20, member l2 will rotate untilthe pin 39 strikes the detent 31, whereupon the member 2| will bepositively stopped, in its zero position. At the same time, member 22 ofthe selector mechanism,

5 by virtue of the instrumentalities previously demagnet 80 is nowenergized, so as to keep mem ber 22 in its detent-engaging (andnon-switchoperating) position.

It will thus be seen that if the key 20 is de pressed for a slightlylonger time than that necessary for acomplete revolution of members 2|and 22 (for instance, in this case, slightly more than 30 seconds) eachof these members will be certain to arrive at its zero position, andthere be positively arrested-whether or not it previously occupied thesame angular position as the other member.

Furthermore, upon release of the key 20, both the motors 32 and 81 stop,so that there can be no further rotation of either of the members 2| and22, even though the concomitant deenergization of magnets 35 and 80necessarily releases the respective stop pins at the two stations. Boththe indicator and selector devices are thus at their zero positions, andtheir respective members 2| and 22 must then step out in unison orsynchronism when key 20 is next depressed, as for the next desiredcontrolling operation. It may be explained that the resonance motors 32and 61 have no appreciable starting lag, and will consequently, on thenext depression of key 20, start to drive the indicator and selectormembers 2| and 22 at once; on the other hand, the electromechanicalcontrol of pins 31 and 9| from the corresponding magnets 35 and 80,particularly by reason of the mechanical linkage involved, is such as topresent a slight lag in the operation of the pins. In consequence, themotors will drive their rotating members away from the zero positionbefore the detent action of the pins is there brought into play, i. e.,before member or pin 31 is shifted (in the indicator mechanism) into thepath of pin 39, and before member 22 (of the selector mechanism) isrocked so as to bring the path of its abutment 9| into intersection withpin 90. As explained, in the apparatus illustrated this delay isafforded by the practically instantaneous starting characteristics ofthe motors, together with the lag necessarily incidental to theelectro-mechanical control of the stop pins, and is thus such as willallow sufficient rotation of the arms 2| and 22 to prevent their beingheld in the starting position by the stop pins. Consequently, theindicator and selector devices are started off in perfect synchronism;and that synchronism is maintained by the natural synchronism of themotors on currents of identical frequency or periodicity.

It will be appreciated that other or additional arrangements may beincluded to provide this delay or lag-for instance, the electro-magneticdevice at each station may be of the delayed action type such asemployed in delayed-action relays.

It will now be understood that when a radio system is employed, i. e.,when the station of Fig. 8 is to be operated by radio from that of Fig.4 as shown, it may be desirable to filter the output of the radioreceiver 81, as in a well known manner--for example, by tuning or by acombination of high and low pass filters, so that. only the frequency towhich the resonance motor 61 is tuned is allowed to pass withappreciable strength. In this way, extraneous impulses caused by staticor interfering radio signals are effectively suppressed and will nothave a tendency to operate the relay in the receiving selectorapparatus.

The receiving apparatus 81 may also conveniently be equipped with anautomatic volume control, such as one of the well known types, so thatits output may remain fairly constant at all times. At the same time, orin lieu of such automatic volume control, some form of output limitingdevice, such as is well known in the art of radio communication, may beplaced between the receiving apparatus 81 and the remainder of thecircuit in Fig. 8 (i. e., on either side of transformer 86) to keep theinput to the selector operating and control devices below apredetermined maximum.

It will now be seen that the arrangement hereinabove described affords aparticularly simple, positive and efiicient system for remote controlpurposes. For example, if the apparatus of Figs. 6 to 11 is disposed ata marine light or fog signal station, the various switching devices 23may be adapted for the control of various electrically actuated orcontrolled devices at that station. They may be connected to control theturning on and oil of the various light or fog signals, and to controlthe automatic transmission (for example, by radio) of telemeteringsignals to the master or shore station, i. e. to indicate there thestate of the apparatus at the light or fog station (voltage ofbatteries, R. P. M. of generators, air pressure in storage tanks, andlike data). It will be understood that the selector apparatus may, ifdesired, be operated by a land wire connection between the stations,either by the directconduction of the desired alternating current or byso-called wired wireless": but it should be apparent that the system isespecially designed for, and particularly advantageous with, theemployment of a carrier wave (wired" or free) to convey the controllingim- Pulses or alternations from the master station to the remote one.

As previously explained, the switching devices shown in Figs. 9 and 10,are, for purposes of illustration, merely a simple set of normallyopened contacts; Fig. 11 shows a double set of normally opened contacts,to be operated by the member 22, and it will now be appreciated thatmany other different types of contact or switching devices, eithernormally open or normally closed or involving a combination of bothtypes, may be substituted for one or more of the specific contactdevices 23 shown in Fig. 5.

It will beunderstood that the invention is not limited to the apparatusand arrangements herein specifically illustrated and described, but maybe embodied in other forms without departure from its spirit as definedby the following claims.

I claim:

1. Apparatus of the character described, comprising a plurality ofselectable switching devices, a remotely located key, a switch-operatingmember movable to select one of the switching devices, means forconcurrently effecting switch selecting movement of said member and uponmovement of said member out of switch-operating position upon depressionof the key and means controlled by the key for causing said member tooperate only the selected switch and only upon release of the key.

2. Apparatus of the character described, comprising an indicator, apluralityof switches, selecting means movable to select a switch to beoperated and having a switch-operating member adapted to be shifted intonon-operating position, means for moving said indicator and saidselecting means in synchronism, said means including a substantiallylag-free resonance motor for each of same and means for supplyingalternating current of the same frequency to both of said motors, meanssettable to arrest said indicator and said selecting means atcorresponding predetermined points and having electromagnetic actuatingdevices therefor, the electromagnetic actuating device for actuating themeans settable to arrest the selecting means being adapted to shift theswitch operating member to non-operating position, and the settablemeans having connections for receiving energizing current concurrentlywith the motors, whereby upon interruption of current supply a switchselected in accordance with movement of the indicator is operated, andwhereby resetting and presynchronization of the indicator and selectingmeans may be effected by establishing current supply to the motors andelectromagnetic devices until the indicator and selecting means arearrested at the predetermined points.

3. In apparatus of the character described, in combination, a movablemember, a motor for moving said member, electrically actuated meansconcurrently energizable with said motor for shifting said membertransversely of its path of movement, and a detent in the path of saidmember when shifted by the last-mentioned means.

4. In apparatus of the character described, in combination, anindicator, a substantially lagfree resonance motor for driving saidindicator, means settable to arrest the indicator at a predeterminedpoint and having an electro-magnetlc actuating device therefor, saidactuating device having an operative lag relative to said motor,

and means for concurrently supplying energizing current to said motorand said actuating device.

5. In apparatus of the character described, in combination, a pluralityof switches, switch operating means movable to select a switch andhaving a substantially lag-free resonance motor for effecting selectingmovement thereof, means settable to arrest selecting movement of saidlastmentioned means at a predetermined point and having anelectro-magnetic actuating device therefor, said actuating device havingan operative lag relative to said motor, and means for concurrentlysupplying energizing current to said motor and said actuating device.

6. The combination of claim 13 in which the switch operating means isadapted to be positively maintained out of switch operating position bythe electro-magnetic actuating device, whereby interruption of currentsupply by the currentsupplying means arrests the motor and effectsoperation of the selected switch.

7. In apparatus of the character described, in combination, a rotatablemember, a detent member, a key, driving means for the rotatable member,including a motor and adapted in response to operation of said key toinitiate rotation of said rotatable member substantially free of lag,and electromagnetic means energizable in response to operation of saidkey for displacing one of the aforesaid members with respect to theother whereby the detent member will be adapted to arrest the rotatablemember at a predetermined position in the path of rotation of thelatter, said last-mentioned mean-s having an operative lag whereby upondepressing the key when the rotatable member is in the saidpredetermined position, the driving means will drive the rotatablemember away from said position before member-displacing operation of theelectromagnetic means occurs.

8. In apparatus of the character described, in combination, a rotatablemember, electrical driving means therefor adapted to initiate rotationof said member substantially free of lag, and cooperating means foreffecting the arrest of said member at a predetermined position, saidcooperating means including an electromagnetic actuating deviceenerglzable concurrently with the electrical driving means, and saidcooperating means having an operative lag relative to said drivingmeans.

9. In apparatus of the character described, in combination, a pluralityof switches independently shiftable for operation, selecting meansmovable past the switches in succession to select a switch to beoperated and having a switch operating member which is adapted to engageand shift the switches and is mounted to rock into and out of switchshifting position, said member being biased to switch-shifting position,a motor for moving the selecting means, electromagnetic means forrocking and holding the aforesaid member out of switch-shiftingposition, means for concurrently supplying current to said motor andelectromagnetic means whereby upon interruption of said current supplythe aforesaid member is caused to operate the selected switch, and adetent at a predetermined point in the path of the aforesaid member pastthe switches, said detent being there disposed to engage the member whenthe latter is out of switch-operating position, for arresting movementof the member at said point.

10. In apparatus of the character described, in combination, switchmeans comprising a plurality of selectable switches, switch selectingand operating means therefor including means responsive to an electricalimpulse of selected duration for driving said second-mentioned means toselect a switch, means normally biasing one of said first and secondmentioned means into switch-operating position relative to the other,and means operated substantially simultaneously with the durationof thedrive-controlling impulse for maintaining the aforesaid first and secondmentioned meansout of switch operating position relative to each other,whereby upon termination of the impulse the selected switch is operatedin response to the biasing means.

11. In apparatus of the character described, in combination, selectableswitches, a switch selector normally in switch-abutting position, meansfor moving the switch selector to select a switch, means brought intoplay when the switch selector is moving, for maintaining the' selectorout of abutment with any of said switches, means for shifting theselector to effect operation of the selected switch upon arrest of theselector adjacent said switch, and means operable when the selector isout of switch-abutting position, to arrest the moving selector at apredetermined point in its path.

, CHARLES F. WALLACE.

CERTIFICATE OF CORRECTION. Patent-No. 2,222,218. November 19, 191m.

J cBARLEs F. WALLACE.

It is hereby certified that error appears in the printed specificationof the above numbered patent requiring correction as follows: Page 5,second column, line 611., for "poietion" reed --poeition-; page L firstcolumn, line 51,. for "member 12" read "member 2l--; page 5, firstcolumn, line h, claim 1, strike out the word "open" and second column,line 53, claim 6, for the claim reference numeral "13" read. --5--; andthat the said Letter: .Patent should be read with this correctiontherein that the some may conform to the record of the case in thePatent Office.

Signed And sealed this 28th day of January, A. 1). 19in.

Henry Van Arsdale, (Seal) Acting Commissioner of Patents.

